Intramolecular Asymmetric Cyclopropanation Using Air Stable Alkylboronic Esters

27 July 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The preparation of polysubstituted bicyclo[3.1.0]hexanes starting from air stable substituted pent-4-en-1-ylboronic esters has been investigated. The method involves a Matteson homologation with LiCHCl2 leading to intermediates 1-chlorohex-5-en-1-yl boronic esters. The intramolecular cyclopropanation step was performed in a one-pot process. With pinacol boronic esters, the cyclopropanation step was either performed thermally at 140 °C or at 70 °C after in situ transesterification to a catechol boronic ester. This last approach is suitable for the preparation of enantioenriched bicyclo[3.1.0]hexanes using either chiral auxiliary control or by taking advantage of the sparteine controlled enantioselective boroalkylation of alcohols.


intramolecular cyclopropanation
boronic esters
Matteson homologation
chiral auxiliary
asymmetric synthesis
enantioselective boroalkylation

Supplementary materials

Experimental part
Synthetic procedures and characterization of all new products including copies of NMR spectra


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